External GNSS Settings
The External GNSS settings screen is where you choose how Mapit GIS receives positions from an external receiver. You can connect over classic Bluetooth SPP, Bluetooth Low Energy, a TCP socket, USB serial, or through a vendor companion app (Eos, Trimble, SXBlue, Leica). Only one connection method is active at a time - enabling a new one automatically disables the others.
- Android
- iOS
Go to Settings - External GNSS to access these options.
Paired Bluetooth (SPP)
| Setting | Default | Description |
|---|---|---|
| Paired Bluetooth GPS | Off | Connect to a receiver that has been paired with the device over classic Bluetooth using the Serial Port Profile (SPP). |
| Selected device | - | Pick a previously paired Bluetooth device by name and MAC address. |
Pair the receiver in Android system Bluetooth settings first, then come back to this screen and tap the device picker.
TCP Connection
| Setting | Default | Description |
|---|---|---|
| TCP GPS | Off | Receive NMEA sentences over a TCP socket. |
| Server | localhost | Hostname or IP address of the NMEA server. |
| Port | 52003 | Port the NMEA server is listening on. |
Useful when positions come from a companion PC, a software GNSS simulator, or a network-exposed receiver.
USB Serial
| Setting | Default | Description |
|---|---|---|
| USB Serial GPS | Off | Connect to a receiver plugged in via USB (USB-to-serial or USB-native GNSS). |
| USB Baud Rate | 115200 | Serial baud rate. Options: 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600. |
When a USB device is connected, Android asks for permission to access it the first time.
BLE (Bluetooth Low Energy)
| Setting | Default | Description |
|---|---|---|
| BLE GPS | Off | Connect to a BLE receiver that exposes the Nordic UART Service (NUS) profile. |
| Selected BLE device | - | Scan and pick a BLE receiver by name. |
BLE is the connection path also used for RTK on receivers such as ArduSimple. The NTRIP client can forward RTCM corrections to the receiver over the same BLE link.
Companion Apps
Toggle the relevant option if you use a vendor app that forwards positions from a high-grade receiver.
| Toggle | Use with |
|---|---|
| Eos Tools Pro | Eos Arrow series receivers |
| Trimble Mobile Manager | Trimble R1, R2, Catalyst, and similar |
| Trimble SPace | Trimble DA2 |
| SXblue Toolbox | Geneq SXblue series |
| Zeno Connect | Leica Zeno GG04, GG03, and compatible |
Only one companion app should be enabled at a time, and the vendor app must be installed separately from the Play Store.
Read next:
- Connecting a Receiver - step-by-step pairing and connection walkthrough for each transport
- GNSS Settings Reference - consolidated reference covering every GNSS-related preference across all settings screens
- GPS Info and Satellites - reading the live fix quality, HDOP/VDOP, and satellite list
- RTK and Fix Types - what the Single, DGPS, RTK Float and RTK Fixed fix types mean
On iOS, external GNSS configuration is part of Survey Settings, not a separate menu entry. Open Settings - Survey Settings and use the GPS source selector. The available options and fields are summarised below - for the full walkthrough see Survey Settings and Connecting a Receiver.
Supported GPS sources on iOS
| Source | Description | Subscription |
|---|---|---|
| Internal GPS | The device's built-in GNSS receiver. | Free |
| TCP/IP NMEA | NMEA stream over a TCP socket. Requires Server host and Port. | Pro |
| Bluetooth Classic | MFi-certified external accessories via Apple's ExternalAccessory framework. | Pro |
| Bluetooth BLE | BLE GNSS receivers that expose the Nordic UART Service (NUS). Tested with u-blox, Emlid, and ArduSimple. | Pro |
USB serial and vendor companion apps (Eos Tools Pro, Trimble Mobile Manager, Zeno Connect, SXblue Toolbox) are Android-only and are not available on iOS.
Bluetooth Classic on iOS
Bluetooth Classic support on iOS uses Apple's ExternalAccessory framework, which requires MFi (Made for iPhone/iPad) certification for every receiver protocol. Apple whitelists each manufacturer's protocol string individually.
Currently whitelisted on iOS:
- Eos Arrow series (Arrow Gold+, Arrow 100, Arrow Lite)
Mapit GIS is actively working with Apple to whitelist additional manufacturers. Until a manufacturer is approved, their Bluetooth Classic receivers cannot be used on iOS - use Bluetooth BLE instead if the receiver supports it, or TCP/IP NMEA if positions can be relayed over the network.
Read next:
- Survey Settings - GPS source selector, per-source connection fields, connection status, and fix quality on iOS
- Connecting a Receiver - step-by-step pairing for Bluetooth Classic, BLE, and TCP/IP on iOS
- GPS Info and Satellites
- RTK and Fix Types